Surfactant compositions comprising solid substrates for subterranean well operations

ABSTRACT

A method of preparing a solid surfactant composite may include: coating a liquid water-wetting surfactant on a solid carrier; and drying the solid carrier to produce the solid surfactant composite. A method may include: introducing a spacer fluid into a wellbore, the spacer fluid comprising a solid surfactant composite; and displacing a fluid in the wellbore using the spacer fluid.

BACKGROUND

The present application is a division of U.S. patent application Ser.No. 16/509,574 filed Jul. 12, 2019, the entirety of which isincorporated herein by reference. 115702

In well cementing operations, such as well construction and remedialcementing, cement compositions are commonly utilized. Cementcompositions may be used in primary cementing operations whereby pipestrings, such as casing and liners, are cemented in wellbores. In atypical primary cementing operation, a cement composition may be pumpedinto an annulus between the exterior surface of the pipe string (e.g.,casing, liner, etc.) disposed therein and the walls of the wellbore (ora larger conduit in the wellbore). The cement composition may set in theannular space, thereby forming an annular sheath of hardened,substantially impermeable material (i.e., a cement sheath) that maysupport and position the pipe string in the wellbore and may bond theexterior surface of the pipe string to the wellbore walls (or the largerconduit). Among other things, the cement sheath surrounding the pipestring should function to prevent the migration of fluids in theannulus, as well as protect the pipe string from corrosion. Cementcompositions may also be used in remedial cementing methods, such as insqueeze cementing for sealing voids in a pipe string, cement sheath,gravel pack, subterranean formation, and the like.

Preparation of the wellbore for cementing operations may be important inachieving optimal zonal isolation. Conventionally, wellbores may becleaned and prepared for the cement composition with a fluid train thatprecedes the cement composition and can include spacer fluids, flushes,and water-based muds, for example. Spacer fluids may be used in wellborepreparation for drilling fluid displacement before introduction of thecement composition. The spacer fluids may enhance solids removal,prepare surfaces for bonding with cement, and separate the drillingfluid from a physically incompatible fluid, such as a cementcomposition. Spacer fluids may also be placed between different drillingfluids during drilling change outs or between a drilling fluid andcompletion brine. A surfactant may be blended with the spacer fluid, forexample, to allow the spacer fluid to be compatible with water- oroil-based drilling fluids. Inclusion of the surfactant may enable thespacer fluid to achieve improved cleaning by removal of residualdrilling fluid from the wellbore. For wellbores in which oil-baseddrilling fluids may have been used, the inclusion of surfactants in thespacer fluids may serve the purpose of water-wetting surfaces in thewellbore, such as the wellbore wall and casing surfaces, resulting inbetter cement bonding.

For cementing operations, whether on land or in subsea operations,addition of liquid surfactants and liquid additives may not be efficientnor adequately controlled. Liquid surfactants may be added to a mixwater feed if the spacer fluid is mixed on the fly using a cementingunit. Alternatively, liquid surfactants may be added to a batch mixerafter pre-hydration of spacer additives and weighting agents arecompleted. In both instances, a mixing vessel with agitation and/orrecirculation capability is required.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate certain aspects of some of the embodiments ofthe present disclosure, and should not be used to limit or define theinvention.

FIG. 1 is a schematic illustration of an example system for thepreparation and delivery of a spacer fluid comprising a solid surfactantcomposite.

FIG. 2 is a schematic illustration of an example in which a spacer fluidcomprising a solid surfactant composite is used between a cementcomposition and a drilling fluid.

FIG. 3 is a schematic illustration of the embodiment of FIG. 3 showingdisplacement of the drilling fluid.

DETAILED DESCRIPTION

Embodiments relate well cementing operations and, more particularly, incertain embodiments, to use of solid surfactant composites in wellcementing operations. The well cementing operations may include the useof the solid surfactant composites in spacer fluids used, for example,in well cementing operations. A solid surfactant composite may be dryblended with particulate solids, wherein the dry blend may be includedin a spacer fluid. One of the many potential advantages to these methodsand compositions is that the use of a solid surfactant composite insteadof liquid surfactants may reduce and potentially eliminate the need foradditional mixing equipment for the surfactant at the well site, thussimplifying preparation of wellbore treatment fluid such as spacerfluids, cements, pills, lost circulation fluids, or any other wellboretreatment fluids. The use of a dry surfactant such as a solid surfactantcomposite disclosed herein may reduce complexity of spacer fluidpreparation. Solid surfactant composites may be dry blended withparticulate solids and weighting agents at a bulk plant which may thenbe mixed on the fly at a well site without the need for additionalmixing vessels to mix a liquid surfactant.

A solid surfactant composite may include a water-wetting surfactant anda solid carrier. Optionally, the solid surfactant composite may includea dispersant, a defoaming agent, or a combination thereof. The solidsurfactant composite may have a wide variety of shapes and sizes ofindividual particles suitable for use in a particular wellboreapplication. By way of example, individual particles of the solidsurfactant composite may have well-defined physical as well as irregulargeometries, including the physical shape of platelets, shavings, fibers,flakes, ribbons, rods, strips, spheroids, hollow beads, toroids,pellets, tablets, or any other physical shape. Without limitation, thesolid surfactant composite may have a particle size in the range ofabout 5 microns to about 1,500 microns and, alternatively, a particlesize in the range of about 20 microns to about 500 microns. However,particle sizes outside these defined ranges also may be suitable forparticular applications.

Any of a variety of water-wetting surfactants may be included in thesolid surfactant composite that may be capable of water-wetting wellsurfaces, such as the wellbore wall and casing surface. In someexamples, the water-wetting surfactant may be in a liquid form, referredto as a liquid water-wetting surfactant, which may be dried on aparticle. The function that a particular surfactant may perform dependson a variety of factors. These factors may include, but are not limitedto, the choice of the hydrophobic and hydrophilic portions and therelative amounts thereof and the presence of any cationic, ionic,non-ionic, amphoteric, or Zwitterionic groups. The water-wettingsurfactant may be included in the solid surfactant composite in anamount, without limitation, of from about 5% to about 99.9% by weight ofthe solid surfactant composite. By way of example, the water-wettingsurfactant may be included in an amount of from about 5%, about 10%,about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, about80%, about 90%, or about 99.9% by weight of the solid surfactantcomposite. The water-wetting surfactants may be ionic, non-ionic,amphoteric, zwitterionic, or any combinations thereof. Examples ofsuitable water-wetting surfactants may include, but are not limited to,homo- and hetero-polymers of alkylene oxides, branched chain alcoholethoxylates, C6-C10 alcohol ethoxylate sulfate ammonium salts,ethoxylated nonylphenols, poly(oxy-1,2,-ethanediyl)alpha-sulfo-omega-(dodecyloxy) ammonium salt, poly(oxy-1,2-ethanediyl)alpha-sulfo-omega-(tetradecyloxy) ammonium salt, ethylene glycolmonobutyl ether, ethoxylated hexanol, 1-methoxy-2-propanol,2-methoxy-1-propanol, C9-C11 alkyl oligomeric d-glucopyranoside, andC9-C11 ethyxylated alcohols.

Other suitable water-wetting surfactants may include alcoholethoxysulfates, alkyl phenol ethoxylates (e.g., nonyl phenolethoxylates), glycol ethers, and combinations thereof. Certain of thewater-wetting surfactants may be used as water-soluble salts. Forexample, the water-wetting surfactants may be selected from alkalimetal, alkaline earth metal, ammonium, and alkanolammonium salts ofalcohol ethoxylates, alcohol ethoxysulfates, and alkyl phenolethoxylates.

Without limitation, suitable alcohol ethoxylates may include C₆ to C₁₆alcohols substituted with from about 2 moles to about 15 moles and,alternatively, from about 5 moles to about 12 moles of ethylene oxide.The C₆ to C₁₅ alcohols may be linear or branched. Without limitation,suitable alcohol ethoxylates may include C₄ to C₈ alcohols substitutedwith about 4 moles to about 8 moles of ethylene oxide, C₈ to C₁₂alcohols substituted with about 4 moles to about 8 moles of ethyleneoxide, and C₁₂ to C₁₄ alcohols substituted with about 10 moles to about14 moles of ethylene oxide. Specific examples of suitable alcoholethoxylates may include butanol, hexanol or pentanol substituted with 6moles of ethylene oxide, nonyl, decyl alcohol, or dodecyl alcoholsubstituted with 6 moles of ethylene oxide, or docecyl alcohol, tridecylalcohol, or tetradecyl alcohol substituted with 12 moles of ethyleneoxide. Additional examples of suitable alcohol ethoxylates may includeisodecyl alcohol substituted with 6 moles of ethylene oxide orisotridecyl alcohol substituted with 12 moles ethylene oxide.Combinations of suitable alcohol ethoxylates may also be used.

Without limitation, suitable alcohol ethoxysulfates may include C₁₀ toC₁₆ alcohols substituted with about 2 moles to about 15 moles ofethylene oxide. The C₁₀ to C₁₆ alcohols may be linear or branched.Suitable C₁₀ to C₁₆ alcohol ethoxylates may include docecyl alcohol,tridecyl alcohol, or tetradecyl alcohol substituted with from 2 moles toabout 15 moles and, alternatively from about 6 moles to about 12 molesof ethylene oxide. Additional examples of suitable alcohol ethoxylatesmay include ethoxylated dodecyl alcohol ammonium sulfate or ethoxylatedtetradecyl ammonium sulfate. Combinations of suitable alcoholethoxysulfates may also be used.

Without limitation, suitable alkyl phenol ethoxylates may include analkyl group with from 1 to 12 carbon atoms and, alternatively, fromabout 8 to 12 carbon atoms. The alkyl phenol ethoxylates may have from 2moles to about 18 moles of ethylene oxide and, alternatively, from about8 moles to about 12 moles of ethylene oxide. One example of a suitablealkyl phenol ethoxylate is nonyl phenol ethoxylate having from about 8moles to about 12 moles of ethylene oxide and, alternatively, about 10moles of ethylene oxide.

Without limitation, suitable glycol ethers may include an alkyl ether ofa mono-, di-, or triethylene glycol. The alkyl ether may include a C₁ toC₅ alkyl ether of a mono-, di-, or triethylene glycol. By way ofexample, the glycol ether may include diethylene glycol methyl ether,dipropylene glycol methyl ether, 2-butoxy ethanol, ethers of a C₂ to C₆dihydric alkanol that include at least one C₁ to C₆ alkyl group, monoethers of dihydric alkanols, methoxypropanol, butoxyethanol,hexoxyethanol, isomers thereof, and combinations thereof. One example ofa suitable glycol ether may include ethylene glycol monobutyl ether. Theglycol ethers may be used by themselves in the solid surfactantcomposite or as a co-surfactant with one or more of the additionalwater-wetting surfactants described herein. Without limitation, a glycolether such as ethylene glycol monobutyl ether may be used as aco-surfactant (50% to 90% by weight) with an alcohol ethoxylates, suchas butanol, hexanol or pentanol substituted with from 4 moles to about 8moles and, alternatively, about 6 moles of ethylene oxide.

As previously described, the water-wetting surfactant may be disposed ona solid carrier. Without limitation, the solid carrier may include anyof a variety of solid materials, such as fly ashes, natural glasses,metal silicates such as aluminosilicates, alkali silicates, and alkaliearth silicates, metal carbonates such as alkali carbonates and alkaliearth carbonates, synthetic glass, biomass ash, diatomaceaous earth,cement kiln dust, lime kiln dust, Portland cement, non-Portland cementssuch as aluminate cement, and combinations thereof. Some specific solidcarriers may include calcium silicate, calcium carbonate, metakaolin,volcanic glass, gypsum, porous alumina, zeolite, porous silica, silicafume, fumed silica, micro fine silica, silica flour, and combinationsthereof. The solid carrier may be included in the solid surfactantcomposite in an amount, without limitation, of from about 0.1% to about95% by weight of the solid surfactant composite. By way of example, thesolid carrier may be included in an amount of from about 0.1%, about10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%,about 80%, about 90%, or about 95% by weight of the solid surfactantcomposite.

Optionally, the solid surfactant composite may include a dispersant.Without limitation, suitable dispersants may include any of a variety ofcommonly used cement dispersants, such as sulfonated dispersants;sulfonated polymer dispersants; naphthalene sulfonates; melaminesulfonates; sulfonated melamine formaldehyde condensate; sulfonatednaphthalene formaldehyde condensate; sulfonate acetone formaldehydecondensate; ethoxylated polyacrylates; or combinations thereof. Oneexample of a suitable dispersant may include a naphthalene sulfonatecondensed with from about 4 moles to about 8 moles and, alternatively,about 6 moles of formaldehyde. The dispersant may be included in thesolid surfactant composite in an amount, without limitation, of fromabout 10% to about 90% by weight of the solid surfactant composite. Byway of example, the dispersant may be included in an amount of fromabout 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about70%, about 80%, or about 90% by weight of the solid surfactantcomposite.

Optionally, the solid surfactant composite may include a defoamingagent. The defoaming agent may be include in the solid surfactantcomposite in addition to, or separate from, the dispersant. Suitabledefoaming agents may include compounds used in well operations toprevent a well treatment fluid from foaming during mixing and pumping.Without limitation, suitable defoaming agents may include oil-baseddefoamers, oil-based defoamers bridged onto particulate carriers,water-based defoamers, silicone-based defoamers, alkylene-oxide baseddefoamers, alkyl polyacrylate based defoamers, and combinations thereof.Other defoamers may include polyol compositions, siloxanes such aspolydimethyl siloxane, acetylenic diols, and combinations thereof. Thedefoaming agent may be included in the solid surfactant composite in anamount, without limitation, of from about 0.1% to about 20% by weight ofthe solid surfactant composite. By way of example, the defoaming agentmay be included in an amount of from about 0.1%, about 5%, about 10%,about 15%, or about 20% by weight of the solid surfactant composite.

Without limitation, a solid surfactant composite may include an alcoholethoxylate, a solid carrier comprising amorphous silica, a dispersant,and a defoaming agent. By way of example, the solid surfactant compositemay include a C₈ to C₁₂ alcohol substituted with about 4 moles to about8 moles of ethylene oxide, amorphous silica, a sulfonated naphthaleneformaldehyde condensate, and a siloxane. By way of further example, thesolid surfactant composite may include isodecyl alcohol substituted with6 moles of ethylene oxide, amorphous silica, naphthalene sulfonatecondensed with 6 moles of formaldehyde, and a polydimethyl siloxane.

Without limitation, a solid surfactant composite may include an alcoholethoxylate, a solid carrier comprising calcium silicate, a dispersant,and a defoaming agent. By way of example, the solid surfactant compositemay include a C₈ to C₁₂ alcohol substituted with about 4 moles to about8 moles of ethylene oxide, amorphous silica, a sulfonated naphthaleneformaldehyde condensate, and a siloxane. By way of further example, thesolid surfactant composite may include isodecyl alcohol substituted with6 moles of ethylene oxide, amorphous silica, naphthalene sulfonatecondensed with 6 moles of formaldehyde, and a polydimethyl siloxane.

Without limitation, a solid surfactant composite may include an alcoholethoxylate, a solid carrier, a dispersant, and a defoaming agent. By wayof example, the solid surfactant composite may include a C₁₂ to C₁₄alcohol substituted with about 10 moles to about 14 moles of ethyleneoxide, amorphous silica, diatomaceous earth, a sulfonated naphthaleneformaldehyde condensate, and a siloxane. By way of further example, thesolid surfactant composite may include isotridecyl alcohol substitutedwith 12 moles ethylene oxide, amorphous silica, diatomaceous earth,naphthalene sulfonate condensed with 6 moles of formaldehyde, and apolydimethyl siloxane.

Without limitation, a solid surfactant composite may include an alcoholethoxylate, a solid carrier, a dispersant, and a defoaming agent. By wayof example, the solid surfactant composite may include a C₁₂ to C₁₄alcohol substituted with about 10 moles to about 14 moles of ethyleneoxide, calcium silicate, a sulfonated naphthalene formaldehydecondensate, and a siloxane. By way of further example, the solidsurfactant composite may include isotridecyl alcohol substituted with 12moles ethylene oxide, amorphous silica, diatomaceous earth, naphthalenesulfonate condensed with 6 moles of formaldehyde, and a polydimethylsiloxane.

The solid surfactant composite may be prepared by any suitabletechnique. By way of example, any combination of the components (e.g.,water-wetting surfactant, solid carrier, dispersant, and/or defoamingagent) may be combined to form a mixture. The mixture may optionallyinclude a carrier fluid such as water, a hydrocarbon, or an alcohol, forexample. The mixture may be sprayed onto the solid carrier and dried toform the solid surfactant composite. Alternatively, the components maybe individually sprayed and dried on the solid carrier to form the solidsurfactant composite. Alternatively, the components may be deposited onthe solid carrier by precipitation, evaporation, including under reducedpressure, and any other method of coating or encapsulation of polymersonto solid substrates.

Without limitation, the solid surfactant composite may be used in aspacer fluid. A spacer fluid may include the solid surfactant compositeand a base fluid. When added to the base fluid, the water-wettingsurfactant on the solid surfactant composite may generally dissolve,with resulting release of the water-wetting surfactant into the basefluid. The solid surfactant composite may be included in the spacerfluid in an amount sufficient for a particular application. Withoutlimitation, the solid surfactant composite may be added to the spacerfluid in an amount in a range of from about 0.1% to about 20% by weightof the spacer fluid and, alternatively, from about 1% to about 5% byweight. For example, the solid surfactant composite may be present in anamount of about 0.1%, about 1%, about 2%, about 4%, about 6%, about 8%,about 10%, about 15%, or about 20% by weight of the spacer fluid.

The base fluid may be an oil-base fluid or aqueous-base fluid. Examplesof aqueous-base fluids may include fresh water, salt water (e.g., watercontaining one or more dissolved salts), brine, seawater, or anycombination thereof. Examples of suitable oil-base fluids may includewater-in-oil emulsions. The base fluid may be used to prepare a spacerfluid that is not emulsified. Without limitation, the base fluid may beincluded in the spacer fluids in an amount in the range of from about15% to about 99.9% by weight of the spacer fluid and, alternatively,from about 25% to about 85% by weight of the spacer fluid. For example,the base fluid may be present in an amount of about 15%, about 20%,about 30%, about 40%, about 50%, about 60%, about 70%, about 80%, about90%, about 99%, or about 99% by weight of the spacer fluid.

The spacer fluids generally should have a density suitable for aparticular application. Without limitation, the spacer fluids may have adensity in the range of from about 4 pounds per gallon (“ppg”) to about24 ppg, in the range of about 4 ppg to about 17 ppg, or in the range ofabout 8 ppg to about 13 ppg. Without limitation, the spacer fluids maybe foamed or unfoamed or include other means to reduce their densitiesknown in the art, such as lightweight additives.

Optionally, the spacer fluid may include a solid particulate additive.The solid particulate additive may be included in the spacer fluid asdesired to perform a particular function. By way of example, the solidparticulate additive may be included in the spacer fluid to weight thefluid to a desired density, assist in well cleaning by abrasive actionin the wellbore, and/or as a viscosifier. Suitable solid particulateadditives may include, without limitation, weighting agents, vitrifiedshale, cement kiln dust, silica flour, bentonite, volcanic glass,natural glass, fly ash, aluminosilicates, and combinations thereof.Weighting agents are typically materials may be used to increase thedensity of a well treatment fluid, such as a spacer fluid, and may havea specific gravity of about 2 or higher (e.g., about 2, about 4, etc.).Examples of weighting agents that may be used include, but are notlimited to, hematite, hausmannite, barite, calcium carbonate, andcombinations thereof. Without limitation, the solid particulate additivemay be included in the spacer fluids in an amount in the range of fromabout 10% to about 85% by weight of the spacer fluid. For example, thesolid particulate additive may be present of about 10%, about 20%, about30%, about 40%, about 50%, about 60%, about 70%, about 80%, or about 85%by weight of the spacer fluid.

Without limitation, the solid particulate additive and the solidsurfactant composite may be dry blended prior to combination with thebase fluid to form the spacer fluid. This dry blend may be preparedoffsite and then transported to the well site, for example, where it maybe combined with the base fluid. By dry blending of the solidparticulate additive and the solid surfactant, preparation of the spacerfluid may be simplified as only one solid additive may need to beincluded in the spacer fluid. In addition, costs may be reduced astransporting of multiple individual solid additives may not be needed ifall the solid additives for the spacer fluid are included in the dryblend. The dry blend may include the solid particulate additive (oradditives) in an amount of from about 80% to about 99.9%, alternatively,from about 90% to about 99.9%, and alternatively, from about 95% toabout 99% by weight of the dry blend. The dry blend may include thesolid surfactant composite in an amount of from about 0.1% to about 20%,alternatively, from about 0.1% to about 10%, and alternatively, fromabout 1% to about 5% by weight of the dry blend.

A wide variety of additional additives may be included in the spacerfluids as deemed appropriate by one skilled in the art, with the benefitof this disclosure. Examples of such additives include, but are notlimited to: viscosifying agents (e.g., clays, hydratable polymers,hydroxyl ethyl cellulose, diutan, welan gum, xanthan gum), fluid losscontrol additives, lost circulation materials, filtration controladditives, dispersants, foaming additives, defoamers, corrosioninhibitors, scale inhibitors, and formation conditioning agents.

Suitable spacer fluids may be prepared in accordance with any suitabletechnique. Without limitation, the desired quantity of water may beintroduced into a mixer (e.g., a cement blender) followed by the dryblend. Without limitation, the dry blend may include the solidsurfactant composite and the solid particulate additive, as describedherein. Additional liquid additives, if any, may be added to the wateras desired prior to, or after, combination with the dry blend. Thismixture may be agitated for a sufficient period of time to form apumpable slurry. By way of example, pumps may be used for delivery ofthis pumpable slurry into the wellbore. As will be appreciated, thespacer fluid and/or the dry blend may be prepared at the well site orprepared offsite and then transported to the well site. If preparedoffsite, the dry blend and/or spacer fluid may be transported to thewell site using any suitable mode of transportation, including, withoutlimitation, a truck, railcar, barge, or the like. Alternatively, thespacer fluid and/or dry blend may be formulated at the well site, forexample, where the components of the spacer fluid and/or dry blend maybe delivered from a transport (e.g., a vehicle or pipeline) and thenmixed prior to placement downhole.

With limitation, the spacer fluid (as described herein) may be used fordisplacing a first fluid from a wellbore, the wellbore penetrating asubterranean formation. The method may include combining componentscomprising a solid surfactant composite, solid particulate additive,and/or a base fluid to provide a spacer fluid. One or more optionaladditives may also be included in the spacer fluid as discussed herein.The method may further include introducing the spacer fluid into thewellbore to displace at least a portion of the first fluid from thewellbore. Without limitation, the spacer fluid may displace the firstfluid from a wellbore annulus, such as the annulus between a pipe stringand the subterranean formation or between the pipe string and a largerconduit. Non-limiting examples of the first fluid displaced by thespacer fluid may include a drilling fluid. By way of example, the spacerfluid may be used to displace the drilling fluid from the wellbore. Inaddition to displacement of the drilling fluid from the wellbore, thespacer fluid may also remove the drilling fluid from the walls of thewellbore. Additional steps in the method may include, withoutlimitation, introducing a pipe string into the wellbore, introducing acement composition into the wellbore with the spacer fluid separatingthe cement composition and the first fluid.

As described herein, the spacer fluid may prevent the cement compositionfrom contacting the first fluid, such as a drilling fluid. The spacerfluid may also remove the drilling fluid, dehydrated/gelled drillingfluid, and/or filter cake solids from the wellbore in advance of thecement composition. Removal of these compositions from the wellbore mayenhance bonding of the cement composition to surfaces in the wellbore.

The displaced drilling fluid may include, for example, any number offluids, such as solid suspensions, mixtures, and emulsions. Anon-limiting example of a suitable drilling fluid may include anoil-based drilling fluid. An example of a suitable oil-based drillingfluid includes an invert emulsion. Without limitation, the oil-baseddrilling fluid may include an oleaginous fluid. Examples of suitableoleaginous fluids that may be included in the oil-based drilling fluidsinclude, but are not limited to, α-olefins, internal olefins, alkanes,aromatic solvents, cycloalkanes, liquefied petroleum gas, kerosene,diesel oils, crude oils, gas oils, fuel oils, paraffin oils, mineraloils, low-toxicity mineral oils, olefins, esters, amides, synthetic oils(e.g., polyolefins), polydiorganosiloxanes, siloxanes, organosiloxanes,ethers, dialkylcarbonates, hydrocarbons, and combinations thereof.

The cement composition introduced into the wellbore may includehydraulic cement and water. A variety of hydraulic cements may beutilized including, but not limited to, those comprising calcium,aluminum, silicon, oxygen, iron, and/or sulfur, which set and harden byreaction with water. Suitable hydraulic cements include, but are notlimited to, Portland cements, pozzolana cements, gypsum cements, highalumina content cements, slag cements, silica cements, and combinationsthereof. In certain embodiments, the hydraulic cement may include aPortland cement. In some embodiments, the Portland cements may includecements classified as Classes A, C, H, or G cements according toAmerican Petroleum Institute, API Specification for Materials andTesting for Well Cements, API Specification 10, Fifth Ed., Jul. 1, 1990.In addition, in some embodiments, the hydraulic cement may includecements classified as ASTM Type I, II, or III.

As will be appreciated, the solid surfactant composite may be used in awide variety of subterranean operations, including well cementingoperations. An example method may include providing a solid surfactantcomposite comprising a water-wetting surfactant and a solid carrier;mixing components comprising the solid surfactant composite and a basefluid to provide a spacer fluid; and introducing a spacer fluid into awellbore such that the spacer fluid displaces a drilling fluid in thewellbore. The solid surfactant composite may be spray dried. The solidsurfactant composite may further include at least one additive selectedfrom the group consisting of a dispersant, a defoaming agent, and anycombination thereof. The water-wetting surfactant includes at least onesurfactant selected from the group consisting of an alcohol ethoxylate,an alcohol ethoxysulfate, an alkyl phenol ethoxylate, a glycol ether,and any combination thereof. The water-wetting surfactant may include analcohol ethoxylate, wherein the alcohol ethoxylate includes C₈ to C₁₂alcohol ethoxylated with about 4 moles to about 8 moles of ethyleneoxide. The solid carrier may include amorphous silica, and wherein thesolid surfactant composite further includes a naphthalene sulfonateformaldehyde condensate and a polydimethyl siloxane. The water-wettingsurfactant may include an alcohol ethoxylate, wherein the alcoholethoxylate includes C₁₂ to C₁₄ alcohol ethoxylated with about 10 molesto about 14 moles of ethylene oxide. The solid carrier may includeamorphous silica and diatomaceous earth, and wherein the solidsurfactant composite further includes a naphthalene sulfonateformaldehyde condensate and a polydimethyl siloxane. The componentsmixed to prepare the spacer fluid may further include a solidparticulate additive, and the mixing comprises mixing a dry blendcomprising the solid surfactant composite and the solid particulateadditive with the base fluid. The solid particulate additive includes atleast one solid material selected from the group consisting of aweighting agent, vitrified shale, cement kiln dust, silica flour,bentonite, natural glass, fly ash, volcanic glass, hematite,hausmannite, barite, calcium carbonate, aluminosilicates, and anycombination thereof. The base fluid may include an aqueous-base fluidselected from the group consisting of fresh water, salt water, brine,seawater, and any combination thereof. The spacer fluid may not beemulsified. The spacer fluid may be introduced into a wellbore annulus.

A composition may be provided that includes a solid surfactant compositecomprising a water-wetting surfactant and a solid carrier; and a solidparticulate additive dry blended with the solid surfactant composite.The solid surfactant composite may be spray dried. The solid surfactantcomposite may further include at least one additive selected from thegroup consisting of a dispersant, a defoaming agent, and any combinationthereof. The water-wetting surfactant includes at least one surfactantselected from the group consisting of an alcohol ethoxylate, an alcoholethoxysulfate, an alkyl phenol ethoxylate, a glycol ether, and anycombination thereof. The water-wetting surfactant may include an alcoholethoxylate, wherein the alcohol ethoxylate includes C₈ to C₁₂ alcoholethoxylated with about 4 moles to about 8 moles of ethylene oxide. Thesolid carrier may include amorphous silica, and wherein the solidsurfactant composite further includes a naphthalene sulfonateformaldehyde condensate and a polydimethyl siloxane. The water-wettingsurfactant may include an alcohol ethoxylate, wherein the alcoholethoxylate includes C₁₂ to C₁₄ alcohol ethoxylated with about 10 molesto about 14 moles of ethylene oxide. The solid carrier may includeamorphous silica and diatomaceous earth, and wherein the solidsurfactant composite further includes a naphthalene sulfonateformaldehyde condensate and a polydimethyl siloxane. The solidparticulate additive includes at least one solid material selected fromthe group consisting of a weighting agent, vitrified shale, cement kilndust, silica flour, bentonite, natural glass, fly ash, hematite,volcanic glass, hausmannite, barite, calcium carbonate, and anycombination thereof.

A system may be provided that may include a solid surfactant compositefor use in a spacer fluid, wherein the solid surfactant compositeincludes a water-wetting surfactant and a solid carrier; a base fluidfor use in the spacer fluid; and a pump fluid fluidly coupled to atubular in fluid communication with a wellbore, wherein the tubular isconfigured to convey the spacer fluid to the wellbore. The system mayfurther include a vessel disposed upstream of the pump, wherein thespacer fluid is disposed in the vessel. The solid surfactant compositemay be spray dried. The solid surfactant composite may further includeat least one additive selected from the group consisting of adispersant, a defoaming agent, and any combination thereof. Thewater-wetting surfactant includes at least one surfactant selected fromthe group consisting of an alcohol ethoxylate, an alcohol ethoxysulfate,an alkyl phenol ethoxylate, a glycol ether, and any combination thereof.The water-wetting surfactant may include an alcohol ethoxylate, whereinthe alcohol ethoxylate includes C₈ to C₁₂ alcohol ethoxylated with about4 moles to about 8 moles of ethylene oxide. The solid carrier mayinclude amorphous silica, and wherein the solid surfactant compositefurther includes a naphthalene sulfonate formaldehyde condensate and apolydimethyl siloxane. The water-wetting surfactant may include analcohol ethoxylate, wherein the alcohol ethoxylate includes C₁₂ to C₁₄alcohol ethoxylated with about 10 moles to about 14 moles of ethyleneoxide. The solid carrier may include amorphous silica and diatomaceousearth, and wherein the solid surfactant composite further includes anaphthalene sulfonate formaldehyde condensate and a polydimethylsiloxane. The components mixed to prepare the spacer fluid may furtherinclude a solid particulate additive, and the mixing comprising mixing adry blend comprising the solid surfactant and the solid particulateadditive with the base fluid. The solid particulate additive includes atleast one solid material selected from the group consisting of aweighting agent, vitrified shale, cement kiln dust, silica flour,bentonite, natural glass, volcanic glass, fly ash, hematite,hausmannite, barite, calcium carbonate, and any combination thereof. Thebase fluid may include an aqueous-base fluid selected from the groupconsisting of fresh water, salt water, brine, seawater, and anycombination thereof. The spacer fluid may not be emulsified. The spacerfluid may be introduced into a wellbore annulus.

Without limitation, methods of using the spacer fluids described hereinin well cementing will now be described in more detail with reference toFIGS. 1-3 . Any of the embodiments of a spacer fluid described hereinmay apply in the context of FIGS. 1-3 . FIG. 1 illustrates a system 100that may be used for preparation and delivery of a spacer fluiddownhole. It should be noted that while FIG. 1 generally depicts aland-based operation, those skilled in the art will readily recognizethat the principles described herein are equally applicable to subseaoperations that employ floating or sea-based platforms and rigs, withoutdeparting from the scope of the disclosure. As illustrated on FIG. 1 ,the system 100 may include a vessel 105 and a pump 110. The pump 110 maybe positioned downstream of the vessel 105 and may be fluidly coupled toa tubular 115 that is in fluid communication with the wellbore 120. Thetubular 115 may be configured to circulate or otherwise deliver thespacer fluid to the wellbore 120. The tubular 115 may be included, forexample, of one or more different pipes that extend into the wellbore120. The pump 110 may be, for example, one or more high pressure or lowpressure pumps, which may be depend on, without limitation, theviscosity and density of the spacer fluid. Without limitation, the pump110 may draw the spacer fluid from the vessel 105, elevate the spacerfluid to an appropriate pressure, and then introduce the spacer fluid tothe tubular 115 for delivery downhole. Without limitation, the vessel105 and pump 110 may be disposed on one or more cement trucks, forexample. While not illustrated, system 100 may further include arecirculating mixer, a batch mixer and/or a jet mixer, which may be usedfor example, in preparation and/or storage of the spacer fluid.Non-limiting additional components that may be present include, but arenot limited to, supply hoppers, valves, condensers, adapters, joints,gauges, sensors, compressors, pressure controllers, pressure sensors,flow rate controllers, flow rate sensors, temperature sensors, and thelike.

FIG. 2 depicts one or more subterranean formations 200 penetrated bywellbore 120 with drilling fluid 205 disposed therein. The drillingfluid 205 may include the example drilling fluids disclosed herein aswell as other suitable drilling fluids. While the wellbore 120 is shownextending generally vertically into the one or more subterraneanformations 200, the principles described herein are also applicable towellbores that extend at an angle through the one or more subterraneanformations 200, such as horizontal and slanted wellbores. Asillustrated, the wellbore 120 includes walls 210. Without limitation, asurface casing 215 may be cemented to the walls 210 of the wellbore 120by cement sheath 220. Without limitation, one or more additional pipestrings (e.g., intermediate casing, production casing, liners, etc.),shown here as casing 225 may also be disposed in the wellbore 120. Asillustrated, there is a wellbore annulus 230 formed between the casing225 and the walls 210 of the wellbore 120 (and/or a larger conduit suchas the surface casing 215). While not shown, one or more centralizersmay be attached to the casing 225, for example, to centralize the casing225 in the wellbore 120 prior to and during the cementing operation.

As illustrated, a cement composition 235 may be introduced into thewellbore 120. For example, the cement composition 235 may be pumped downthe interior of the casing 225. A pump (e.g. pump 110 on FIG. 1 ) may beused for delivery of the cement composition 235 into the wellbore 120.It may be desired to circulate the cement composition 235 in thewellbore 120 until it is in the wellbore annulus 230. The cementcomposition 235 may include the example cement compositions disclosedherein as well as other suitable cement compositions. While notillustrated, other techniques may also be utilized for introduction ofthe cement composition 235. By way of example, reverse circulationtechniques may be used that include introducing the cement composition235 into the wellbore 120 by way of the wellbore annulus 230 instead ofthrough the casing 225.

Without limitation, the spacer fluid 240 may be used to separate thedrilling fluid 205 from the cement composition 235. The previousdescription with reference to FIG. 1 for preparation of a spacer fluidmay be used for delivery of the spacer fluid 240 into the wellbore 120.Moreover, a pump (e.g., pump 110 on FIG. 1 ) may also be used fordelivery of the spacer fluid 240 into the wellbore 120. The spacer fluid240 may be used with the cement composition 235 for displacement of thedrilling fluid 205 from the wellbore 120 as well as preparing thewellbore 120 for the cement composition 235. By way of example, thespacer fluid 240 may function, inter alia, to remove the drilling fluid205, drilling fluid 205 that is dehydrated/gelled, and/or filter cakesolids from the wellbore 120 in advance of the cement composition 235.While not shown, one or more plugs or other suitable devices may be usedto physically separate the drilling fluid 205 from the spacer fluid 240and/or the spacer fluid 240 from the cement composition 235.

Referring now to FIG. 3 , the drilling fluid 205 has been displaced fromthe wellbore annulus 230. As illustrated, the spacer fluid 240 and thecement composition 235 may be allowed to flow down the interior of thecasing 225 through the bottom of the casing 225 (e.g., casing shoe 300)and up around the casing 225 into the wellbore annulus 230, thusdisplacing the drilling fluid 205. At least a portion of the displaceddrilling fluid 205 may exit the wellbore annulus 230 via a flow line 125and be deposited, for example, in one or more retention pits 130 (e.g.,a mud pit), as shown in FIG. 1 . Turning back to FIG. 3 , the cementcomposition 235 may continue to be circulated until it has reached adesired location in the wellbore annulus 230. The spacer fluid 240 (or aportion thereof) and/or the cement composition 235 may be left in thewellbore annulus 230. As illustrated, the spacer fluid 240 may bedisposed in the wellbore annulus 230 above or on top of the cementcomposition 235. The cement composition 235 may set in the wellboreannulus 230 to form an annular sheath of hardened, substantiallyimpermeable material (i.e., a cement sheath) that may support andposition the casing 225 in the wellbore 120.

Statement 1. A method of preparing a solid surfactant compositeincluding: coating a liquid water-wetting surfactant on a solid carrier;and drying the solid carrier to produce the solid surfactant composite.

Statement 2. The method of statement 1 wherein the step of coatingincludes dry blending or spraying.

Statement 3. The method of any of statements 1-2 wherein the step ofcoating includes spraying and wherein the method further includesspraying at least one of a dispersant, a defoamer, or both.

Statement 4. The method of any of statements 1-3 wherein the liquidwater-wetting surfactant, the dispersant, and the defoamer areindividually sprayed on the solid carrier or sprayed as any mixturethereof.

Statement 5. The method of any of statements 1-4 further comprising:

mixing the liquid water-wetting surfactant, the dispersant, and thedefoamer with a carrier fluid prior to the step of spraying.

Statement 6. The method of any of statements 1-5 wherein the liquidwater-wetting surfactant includes at least one surfactant selected fromthe group consisting of an alcohol ethoxylate, an alcohol ethoxysulfate,an alkyl phenol ethoxylate, a glycol ether, or any combination thereof.

Statement 7. The method of any of statements 1-6 wherein the solidcarrier includes calcium silicate.

Statement 8. The method of any of statements 1-7 wherein the solidcarrier includes at least one of as fly ash, natural glass, metalsilicates, aluminosilicates, alkali silicates, alkali earth silicates,metal carbonates, alkali carbonates, alkali earth carbonates, syntheticglass, biomass ash, diatomaceaous earth, cement kiln dust, lime kilndust, Portland cement, non-Portland cement, aluminate cement, andcombinations thereof.

Statement 9. A method comprising: introducing a spacer fluid into awellbore, the spacer fluid comprising a solid surfactant composite; anddisplacing a fluid in the wellbore using the spacer fluid.

Statement 10. The method of statement 9 wherein the solid surfactantcomposite includes: a liquid water-wetting surfactant disposed on asurface of a solid carrier; and, optionally, a dispersant, a defoamer,or both disposed on a surface of the solid carrier.

Statement 11. The method of any of statements 9-10 wherein the solidsurfactant composite is prepared by coating a liquid water-wettingsurfactant, and, optionally, the dispersant, the defoamer, or both onthe solid carrier and drying the drying the solid carrier to produce thesolid surfactant composite.

Statement 12. The method of any of statements 9-11 wherein the solidcarrier includes calcium silicate.

Statement 13. The method of any of statements 9-12 wherein the solidcarrier includes at least one of as fly ash, natural glass, metalsilicates, aluminosilicates, alkali silicates, alkali earth silicates,metal carbonates, alkali carbonates, alkali earth carbonates, syntheticglass, biomass ash, diatomaceaous earth, cement kiln dust, lime kilndust, Portland cement, non-Portland cements, aluminate cement, andcombinations thereof.

Statement 14. The method of any of statements 9-13 wherein the liquidwater-wetting surfactant includes at least one surfactant selected fromthe group consisting of an alcohol ethoxylate, an alcohol ethoxysulfate,an alkyl phenol ethoxylate, a glycol ether, and any combination thereof.

Statement 15. The method of any of statements 9-14 wherein liquid thewater-wetting surfactant includes an alcohol ethoxylate, wherein thealcohol ethoxylate includes C₈ to C₁₂ alcohol ethoxylated with about 4moles to about 8 moles of ethylene oxide.

Statement 16. The method of any of statements 9-15 wherein the spacerfluid further comprises an aqueous-base fluid selected from the groupconsisting of fresh water, salt water, brine, seawater, and anycombination thereof.

Statement 17. The method of any of statements 9-16 further comprisingpreparing the spacer fluid, the preparing comprising: mixing a dry blendcomprising the solid surfactant and a solid particulate additive with amaqueous-base fluid.

Statement 18. A method comprising: introducing a spacer fluid into awellbore, the spacer fluid comprising a solid surfactant composite, thesolid surfactant composite comprising a surfactant coated on a calciumsilicate solid carrier; and displacing a fluid in the wellbore using thespacer fluid, wherein the solid surfactant composite is prepared bycoating a liquid water-wetting surfactant, on the solid carrier anddrying the drying the solid carrier to produce the solid surfactantcomposite.

Statement 19. The method of statement 18 wherein the water-wettingsurfactant comprises at least one surfactant selected from the groupconsisting of an alcohol ethoxylate, an alcohol ethoxysulfate, an alkylphenol ethoxylate, a glycol ether, or any combination thereof.

Statement 20. The method of any of statements 18-19 wherein the solidsurfactant further comprises at least one of a dispersant, a defoamer,or both coated on the calcium silicate solid carrier.

The exemplary spacer fluid disclosed herein may directly or indirectlyaffect one or more components or pieces of equipment associated with thepreparation, delivery, recapture, recycling, reuse, and/or disposal ofthe sugar cane ash and associated spacer fluids. For example, the spacerfluid (or components thereof) may directly or indirectly affect one ormore mixers, related mixing equipment, mud pits, storage facilities orunits, composition separators, heat exchangers, sensors, gauges, pumps,compressors, and the like used generate, store, monitor, regulate,and/or recondition the exemplary sugar cane ash and fluids containingthe same. The disclosed spacer fluid (or components thereof) may alsodirectly or indirectly affect any transport or delivery equipment usedto convey the spacer fluid (or components thereof) to a well site ordownhole such as, for example, any transport vessels, conduits,pipelines, trucks, tubulars, and/or pipes used to compositionally movethe spacer fluid (or components thereof) from one location to another,any pumps, compressors, or motors (e.g., topside or downhole) used todrive the spacer fluid (or components thereof), into motion, any valvesor related joints used to regulate the pressure or flow rate of thespacer fluid, and any sensors (i.e., pressure and temperature), gauges,and/or combinations thereof, and the like. The disclosed spacer fluidmay also directly or indirectly affect the various downhole equipmentand tools that may come into contact with the spacer fluid such as, butnot limited to, wellbore casing, wellbore liner, completion string,insert strings, drill string, coiled tubing, slickline, wireline, drillpipe, drill collars, mud motors, downhole motors and/or pumps, cementpumps, surface-mounted motors and/or pumps, centralizers, turbolizers,scratchers, floats (e.g., shoes, collars, valves, etc.), logging toolsand related telemetry equipment, actuators (e.g., electromechanicaldevices, hydromechanical devices, etc.), sliding sleeves, productionsleeves, plugs, screens, filters, flow control devices (e.g., inflowcontrol devices, autonomous inflow control devices, outflow controldevices, etc.), couplings (e.g., electro-hydraulic wet connect, dryconnect, inductive coupler, etc.), control lines (e.g., electrical,fiber optic, hydraulic, etc.), surveillance lines, drill bits andreamers, sensors or distributed sensors, downhole heat exchangers,valves and corresponding actuation devices, tool seals, packers, cementplugs, bridge plugs, and other wellbore isolation devices, orcomponents, and the like.

The preceding description provides various embodiments of the spacerfluids containing different additives and concentrations thereof, aswell as methods of using the spacer fluids. It should be understoodthat, although individual embodiments may be discussed herein, thepresent disclosure covers all combinations of the disclosed embodiments,including, without limitation, the different additive combinations,additive concentrations, and fluid properties.

It should be understood that the compositions and methods are describedin terms of “comprising,” “containing,” or “including” variouscomponents or steps, the compositions and methods can also “consistessentially of” or “consist of” the various components and steps.Moreover, the indefinite articles “a” or “an,” as used in the claims,are defined herein to mean one or more than one of the element that itintroduces.

For the sake of brevity, only certain ranges are explicitly disclosedherein. However, ranges from any lower limit may be combined with anyupper limit to recite a range not explicitly recited, as well as, rangesfrom any lower limit may be combined with any other lower limit torecite a range not explicitly recited, in the same way, ranges from anyupper limit may be combined with any other upper limit to recite a rangenot explicitly recited. Additionally, whenever a numerical range with alower limit and an upper limit is disclosed, any number and any includedrange falling within the range are specifically disclosed. Inparticular, every range of values (of the form, “from about a to aboutb,” or, equivalently, “from approximately a to b,” or, equivalently,“from approximately a-b”) disclosed herein is to be understood to setforth every number and range encompassed within the broader range ofvalues even if not explicitly recited. Thus, every point or individualvalue may serve as its own lower or upper limit combined with any otherpoint or individual value or any other lower or upper limit, to recite arange not explicitly recited.

Therefore, the present disclosure is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent disclosure may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. Also, the terms in the claimshave their plain, ordinary meaning unless otherwise explicitly andclearly defined by the patentee. It is therefore evident that theparticular illustrative embodiments disclosed above may be altered ormodified and all such variations are considered within the scope andspirit of the present disclosure. If there is any conflict in the usagesof a word or term in this specification and one or more patent(s) orother documents that may be incorporated herein by reference, thedefinitions that are consistent with this specification should beadopted.

What is claimed is:
 1. A method of preparing a solid surfactantcomposite comprising: spraying a mixture comprising a liquidwater-wetting surfactant comprising an alcohol ethoxylate, a dispersantcomprising naphthalene sulfonate, a defoamer comprising polydimethylsiloxane, and a carrier fluid comprising an alcohol on a solid carriercomprising calcium silicate as a single liquid coating; and after thestep of spraying, drying the solid carrier and the single liquid coatingto produce the solid surfactant composite, wherein after drying, thesolid surfactant composite comprises dried water-wetting surfactant,dried dispersant, and dried defoamer.
 2. The method of claim 1, furthercomprising: mixing the liquid water-wetting surfactant, the dispersant,and the defoamer with the carrier fluid prior to the step of spraying.3. The method of claim 2, wherein the carrier fluid further comprises atleast one fluid selected from a list consisting of water, a hydrocarbon,and any combination thereof.
 4. The method of claim 1, wherein theliquid water-wetting surfactant further comprises at least onesurfactant selected from the group consisting of an alcoholethoxysulfate, an alkyl phenol ethoxylate, a glycol ether, and anycombination thereof.
 5. The method of claim 1, wherein the calciumsilicate is present in the solid surfactant composite in an amount ofabout 0.1 wt. % to about 10 wt. % by weight of the solid surfactantcomposite.
 6. The method of claim 1, wherein the solid surfactantcomposite has a mean diameter of about 5 microns to about 1500 microns.7. The method of claim 1, wherein the liquid water-wetting surfactantcomprises alcohol ethoxylate, wherein the alcohol ethoxylate is presentin an amount of about 15 wt. % to about 30 wt. % by weight of the solidsurfactant composite.
 8. The method of claim 1, wherein the liquidwater-wetting surfactant further comprises alcohol ethoxylate sulfateammonium salt.
 9. The method of claim 1, wherein the liquidwater-wetting surfactant further comprises a C₈ to C₁₂ alcoholethoxylated with about 4 moles to about 8 moles of ethylene oxide. 10.The method of claim 1, wherein the solid carrier further comprises atleast one solid carrier selected from the group consisting of fly ash,natural glass, metal silicates, amorphous silica, aluminosilicates,alkali silicates, alkali earth silicates, metal carbonates, alkalicarbonates, alkali earth carbonates, synthetic glass, biomass ash,diatomaceous earth, cement kiln dust, lime kiln dust, Portland cement,non-Portland cement, aluminate cement, and any combination thereof. 11.The method of claim 1, wherein the liquid water-wetting surfactantfurther comprises at least one surfactant selected from the groupconsisting of poly(oxy-1,2,-ethanediyl) alpha-sulfo-omega-(dodecyloxy)ammonium salt, poly(oxy-1,2-ethanediyl)alpha-sulfo-omega-(tetradecyloxy) ammonium salt, C9-C11 alkyl oligomericd-glucopyranoside, and any combination thereof.
 12. The method of claim1, wherein the dispersant further comprises at least one dispersantselected from the group consisting of a sulfonated polymer, a melaminesulfonate, a sulfonated melamine formaldehyde condensate, a sulfonatednaphthalene formaldehyde condensate, sulfonate acetone formaldehydecondensate, ethoxylated polyacrylates; and any combination thereof. 13.The method of claim 1, wherein the defoamer comprises at least onedefoamer selected from the group consisting of oil, silicone, analkylene-oxide, an alkyl polyacrylate, polyol, siloxane, acetylenicdiol, and any combination thereof.